Identification of the occurrence and pattern of masseter muscle activities during sleep using EMG and accelerometer systems.

Yoshimi H, Sasaguri K, Tamaki K, Sato S - Head Face Med (2009)

Bottom Line:
The system consisted of a 2-axis accelerometer, electroencephalography and electromyography.Results showed that grinding (59.5%) was most common, followed by clenching (35.6%) based on relative activity to maximum voluntary contraction (%MVC), whereas tapping was only (4.9%).It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals.

Affiliation: Department of Craniofacial Growth and Development Dentistry, Research Institute of Occlusion Medicine, Research Center of Brain and Oral Science, Kanagawa, Japan. info@yoshimishika.com

ABSTRACT

Background: Sleep bruxism has been described as a combination of different orofacial motor activities that include grinding, clenching and tapping, although accurate distribution of the activities still remains to be clarified.

Methods: We developed a new system for analyzing sleep bruxism to examine the muscle activities and mandibular movement patterns during sleep bruxism. The system consisted of a 2-axis accelerometer, electroencephalography and electromyography. Nineteen healthy volunteers were recruited and screened to evaluate sleep bruxism in the sleep laboratory.

Results: The new system could easily distinguish the different patterns of bruxism movement of the mandible and the body movement. Results showed that grinding (59.5%) was most common, followed by clenching (35.6%) based on relative activity to maximum voluntary contraction (%MVC), whereas tapping was only (4.9%).

Conclusion: It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals.

Figure 5: Distribution of bruxism event length into the different patterns of bruxism. There was a tendency for subjects who had long bruxism event duration to show increasing grinding event duration and decreasing clenching and tapping event durations.

Mentions:
Comparisons of the duration of bruxism-events demonstrated that individuals who had high muscle activity (%MVC) also tended to show long event duration similar to volunteers 18 and 19, whereas individuals with moderate muscle activity (%MVC) showed relatively long event duration such as volunteers 14 (Fig. 5).

Figure 5: Distribution of bruxism event length into the different patterns of bruxism. There was a tendency for subjects who had long bruxism event duration to show increasing grinding event duration and decreasing clenching and tapping event durations.

Mentions:
Comparisons of the duration of bruxism-events demonstrated that individuals who had high muscle activity (%MVC) also tended to show long event duration similar to volunteers 18 and 19, whereas individuals with moderate muscle activity (%MVC) showed relatively long event duration such as volunteers 14 (Fig. 5).

Bottom Line:
The system consisted of a 2-axis accelerometer, electroencephalography and electromyography.Results showed that grinding (59.5%) was most common, followed by clenching (35.6%) based on relative activity to maximum voluntary contraction (%MVC), whereas tapping was only (4.9%).It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals.

Affiliation:
Department of Craniofacial Growth and Development Dentistry, Research Institute of Occlusion Medicine, Research Center of Brain and Oral Science, Kanagawa, Japan. info@yoshimishika.com

ABSTRACT

Background: Sleep bruxism has been described as a combination of different orofacial motor activities that include grinding, clenching and tapping, although accurate distribution of the activities still remains to be clarified.

Methods: We developed a new system for analyzing sleep bruxism to examine the muscle activities and mandibular movement patterns during sleep bruxism. The system consisted of a 2-axis accelerometer, electroencephalography and electromyography. Nineteen healthy volunteers were recruited and screened to evaluate sleep bruxism in the sleep laboratory.

Results: The new system could easily distinguish the different patterns of bruxism movement of the mandible and the body movement. Results showed that grinding (59.5%) was most common, followed by clenching (35.6%) based on relative activity to maximum voluntary contraction (%MVC), whereas tapping was only (4.9%).

Conclusion: It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals.